Method of signaling.



R. A. FBSSENDEN. METHOD OF SIGNALING. APPLICATION rum) JAN. 24, .1908.

Patented Jun21,1910.

Patentd June 21, 1910.

2 snnn'rs-sunn'r 2.

61 W a if? may the receiving tercepted or modified except upon receipt of REGINALD A. 'FESSENDEN,

OF BRANT ROCK, MASSACHUSETTS.

mn'rn'on OFSSIGNALING.

962,018. Original applicationflled October 10,

Specification of Letters Patent.

1907, Serial No. 396,817. Divided and this application filed June 24,

1908. Serial No. 412,417.

Patented June 21, 1910.

To all whom "it may concern:

Be it known that I, REGINALD A. FESSEN- DEN, a citizen of the United States, residing at Brant Rock, in the State of Massachusetts, have invented certain new and useful Methods of Signaling, of which the following is a specification.

My invention relates to the art of wireless signaling generally, and in some particulars especially to preventing interference in signaling. Its objects will appear hereinafter.

These objects, and other advantages which will hereinafter appear I attain by means of apparatus illustrated here and in my copen ing application No. 396,817 filed Octobe'r 10th, 1907, of which this application is a division.

In the accompanying drawings which illustrate my methods in several forms, .Figure 1 is a diagram of sending apparatus; Fig. 2 is a diagram showing modified arirangelnents of circuits for sending; Figs. 3 and 4 are diagrams of arrangements of receiving apparatus in two forms; Figs. 5 and 6 show respectively in section and side elevation a convenient means for generating electro-magnetic waves. 1

It has been customary to signal by sending at intervals certain trains of electromagnetic waves which vary in length or intensity or character to represent the dots and dashes of a Morse code and since all operators are familiar with the signals it is easy to read them. I avoid this and other objections, as well as gain certain fisychological advantages by sending or mo ifying waves not for the-dots and dashes but the spaces between dots and dashes, thus inverting the signals. It has also been customary to use receiving instruments which respond only to the signal, whereas in my method a continuous stream of impulses is kept up at station and this stream is inthesignals, which prevents any disturbance by other stations unlessthe frequency is of exactl the same tune. Other characteristics o my method will appear hereafter.

In the sendin arrangement as'illustrated in Fig. 1, a big frequency'alternating dyname 11 and a tuning inductance 12 are inserted in the sending conductor having the antenna 13 and grounded at 14:. This antenna may otherwise be ofthe' loop type, in

-t is is notnecessary.

which caseit is preferred not to ground it.

15 represents the field of the dynamo 11, i

which is excited by a source 16 having in circuit a key 17, which is so arran ed that when it is depressed it opens the old circuit and stops the emission of high frequency oscillations, which normally are sent out in a continuous stream. That is, when the key is in normal position electro-magnetic Waves are being sent out, and when it is depressed this stream of waves is interrupted, thus signaling not the dots and dashes after the usualmethod, but the spaces between. 1

In Fig. 2 I have shown in th'e circuit of the antenna 13,.the primary 18 of a transformer of which the secondary 19 is in circuit with an inductance 22 which has a key 23 arranged to short circuit it. Also in this circuit is the primary 24 of another trans former whose secondary 25 has in circuit a capacity 26, an inductance 27, a spark gap 29, winch is preferably a compressed as gap; also an adjustable resistance 30, and a source of continuous lcurrent 31. There is also a high frequency alternating current dynamo 33, which may be alternately used by throwing the switch 32 as will be evident. In the circuits as arranged the couplings of the transformers 18, 19, and 24, 25 res ectively, are preferabl different, though Ii. will be observed that waves are generated and emitted continuously but when the key 23 is de ressed, the frequency of the waves is altere which change will be detected at the receiving station.

The electrical constants of the circuits are preferablyjso arranged that the frequency will be less than 100,000 when it is desired to send over long distances; this because I have discovered by ex eriment that the absorption over long distances is very much less for frequencies of this value or less, than with higher frequencies. For example with a frequency of 50,000,there is comparatively little absorption up to a distance of 2,000 miles, in daylight, whereas with 'a frequency of 200,000 t are is almost a total absorption. In Fig. ,3 I show a form of 'reoeivin apparatus. The antenna 34 grounded at 3 contains the primary 35 of a transformer whose secondary 36 is connected to a demag- By means of pulleysv 42, 43, driven as by motor 44 a soft iron wire 41 is continuouslg toward coil 38. I

a is energized by battery les of magnet 38 an of magnet 45 which 46 and magnetizes the non wire as it passes in the direction rovide a strin vibrator passed between the also between the p'e Y shown at-the top the fi ure an actuated The iron wire 41 thus by coil 47 which is excited ybattery the wire an-undulating or alternating mag netism, preferablyof an audible frequency. having a succession of variationswhich if heard would produce a musical note, passes between the poles of magnet coil 51, after traversing the poles of coil'38. In clrcuit with this coil 51 is a ,telephone receiver 52, and itv will thus-be seen that without interference of the sending apparatus a continuous note would be heard. But when the sending key 17 or 23 musical note in the telephone,

key 17 of Fig. l is depressed or o ned; or.

. key 23. That is,

asabove described gin Figs. 1. and 2) is in normal condition (0 osed in Fig. 1 and open in- Fig. the waves emitted and received 2 at 38 will eliminate orpartly suppress the by annulling the magnetism and orderly succession of variations in wire 41, thus wi ingofi the musical note and leaving-assent space, until way. the I inverted sendmg is corrected in turn by an inverted receiving, and the dots and dashescome out as musical notes.

In the modification of Fig. 4 the circuit of the secondary 36, containing the capacit 39 and inductance 40, has a receiver 53 such as a liquid barretter or tellurium receiver,

become balanced, and thus cut and'inc udes also\coils 55 and 56 of a trans- .former, and also a capacity57 and adjustable resistance 58. 54 represents a tuning fork vibrator constantly producing a musical note, and by means of the primary 48 a secondary 49, the divided circuits 55, 53, 56, and" 57, 58, 56 are effected with the frequency of this musical note. A tele hone receiver 62 is connected in circuit wi the secondaries 60, 61 of the transformer, and the resistance 58 and the capaci 57 are so adjusted that a continuous soun would be produced, in the telephone 62, when in normal condition, but when waves of the strength produced b the ro r sending station are received, t e two 'vlded circuits .88 and by means of coils 48, 49, the coil 50is given an undulating current which impresses on' as 88'and 87 in Fi concentrical the armatures are out the sound in the. telephone. accomplishes the are sent in inverted form. It will be- ;same purpose of reinverting the signals as un erstood that the method may be used in connection with a ceiver, in which t e signal is reduced b direct interaction of the receive and locally produced currents, and with mechanical group tuning; but the particular kind of receiver and particular method of tuning, etc., are not material to the invention.

It is highly desirable in operating this method to have a particularly efiicient enerator, and in connection with the met od illustrated'in Fig. 2 I have shown a special form of generator (more full described in my .00" endin application 0. 393,235 of Septem r 16t 1907), and means for operating with it, in Figs. 5 and 6. A revolving slotted disk 63 with teeth 92 wound as shown in dotted lines in Fig. 6, travels between the armatures 64 and 65, which are supported resiliently and indirectly by bearings 66 and 67 mounted onthe shaft 68 carr ing the disk 63 and held stationary in the rams by stop 84. The bearings are connected indirectly to the armatures by dash pots such g. 6, and arms 85, 86 with similar devices 93. By this means the armature is supported flexibly and yet always y with the revolving shaft 68 of the disk. A field coil 6", is rovided,-in the casing 90, and armature 65 is connected through capacity 71 with a fixedcoil 72,

' while the armature 64 is connected through capacity 70 to fixed coil73. These'coils are grounded at 75 while the other terminals of grounded through the frame of the machine as at 76. The laminated rings 83 complete the magnetic circuit. Coils 72 an'd'73 are to each other so that the? inductive efiect. Aroun exert no -mutual plicants heterodyne rev set at right angles them is a movable can 77 having an-arm 82 which is ca a- I ble of being swung angularly by the action of the coil 80, excited by a battery 31. The core 81 and lever arms '82 are thus operated when the key 78 is depressed and turns the coil 77 from a position parallel to one of the coils 72, 73, to the other. 'Coil 77 is connected to antenna 84 throu h a tuning inductance 83, and to groung at 74. Shifting the key thus changes the frequency of the emitted waves while keeping their intensity constant.

The apparatus herein described is not here station.

claimed, but is claimed in the co-pending aren-t application No. $96,817 abovereerred to.

Having thus'described my invention and illustrated its use, what I herein claim as new and desireto secure by Letters Patent, is the following:

1. The method of signaling by maintaining a continuous flow of impulses at a recerving station, normally annulling their effeet by received impulses sent from another station, and signaling by modifying the sent impulses and thus interrupting said normal annulment.

2. The method of signaling by producin a continuous stream 0 impulses at a. sen ing station, maintaining a continuous stregm of impulses at a receivin station and nor: mally annulling their efi act by the agency of the sent impulses, and signalin by modifying the stream of impulses at t 3.The method of signaling by sending and receivin a continuous stream of electric impulses an normall annulling by their energy a continuous ow of im ulses at a receiving station, and signaling by altering the sent impulses so as to allow the impulses at the recelving station to operate an indieating instrument.

4. he 'method of signalingby'maintaining a continuous flowof impulses at each of two intercommunicating stations and modif in the character of impulses at one staat the'receiving station rupting them to t1on y the energy of those-from the other, and signalingby alterin the character of the sent' impulses to there y omit said modification at the receiving station.

5. The inverted method of signaling which comprises transmitting electro-magnetic waves continuously exce t for, interrepresent tiie dashes of a code, and reinverting the signals terru tions only to be sensible.

6.v n the art of signalin which comprises generating e ectro-magnetic waves wit practical continuity, maintainin a continuous sensible indication at areceiving station independent of the waves re.- ceived, and normally altering their character. by the waves as received.

7. In wireless telegraphy, the method which consists in continuously generating and emitting waves; and chan 'ng their character to represent dots 'an dashes of an alphabet, maintaining at a receiving station a continuous flow of impulses normally neutralized by the waves received and cansing the abnormal received waves representing the dots and dashes to interru t the neutralizing of said continuous local indication, to produce a signal.

8. In the art of wireless signaling, the

method which comprises sending continuous e sending,

' 7 normally suppressing the1r dots and bycausin'g the in-' the method impulses at a sendlng station,

waves representing spaces and interrupting them to represent dots and dashes.

9. In the art of wireless signaling, the method which comprises maintainin at a receiving station, a continuous sensi le in= dication and normally'modifying its efiect form signals.

'10. In. wireless signaling, the method which comprisessending normally continuous electric waves, maintainin normally 'a continuous series of im ulses or producing a sound indication at the receiving station, adapted to be normally silenced by the received waves, and changin the character of said sent waves, thus al owing the local sound to be heard.

11. In signaling b electro-magnetic waves, the process whic comprises the continuous roduction at the receiving station of impu ses for producing a musical sound,

naling by mo ifying the suppressing means to permit the sound to be reduced.

12. The invertedmethod of signaling by sending and receiving a sustained flow 0 electric impulses of definite character to represent spaces, and signaling by altering thelr character to represent dots and dashes in a code and re-inverting and making only said dots and dashes sensible at the receiving station.

13. Themethod of signaling by sending a sustained normal. flow of impulses of definite character, maintaining a continu'ous flow of local impulses-at a receiving station, and modifying them by the rece1ved impulses and modifying the normal flow at the sending station to roduce a signal by interruptingthe norma modification of the local impulses.

14. The method of signalin by maintaining a continuous flow o impu ses at eachof two intercommunicating stations, normally modifying the character of the im ulses at one station by the energy of those om the by received waves except at intervals to other, and signaling by-altering the character of the/sent impulses to thereby change said modification at the receiving station.

15. The method of signaling by maintaining a continuous flow of impulses for producing sound waves at a receiving station, normally annullin them by electro magnetic waves emitte from a sending station, and signaling by altering the sent waves and thus interrupting the said annulment.

16. The method of electric signaling which" a continuous stream of. maintaining acontinuous stream of impulses at a receiving station and norma ly suppressing their efiect-by" means of the sent lmpulses, and signaling by interrupting the stream" of sent? im ulses.

comprises producing e method of electric signaling which comprises transmitting electromagnetic. waves normally continuously and modifying their character to represent dots and dashes ofv a code, and reinverting such si nals at the receiving station by causing t e normally continuous stream to be silenced, and causing the modifications only to be sensible. i

18. The inverted. 'method of si which comprises sendifie: norma y continuous stream of imp and interru ting it to represent dots and dashes, mamtaming at the receiving 'statlon a continuous ailing,

stream .of impulses, and normally silencin I them by the sent impulses, whereby the loca 5 impulses produce an effect when the silencing influence is removed by interrupting the transmitted im ulses.

In testimony w ereof I have hereunto signed in name in the presence of the two 2 subscribe witnesses.

REGINALD A. FESSENDEN.

Jnssre E. BENT, J. W. LEE. 

